Evaluating Clinical Rating Scales for Evidence-Based Dermatology: Some Basic Concepts

Madhulika A. Gupta, The University of Western Ontario
Andrew M. Johnson, The University of Western Ontario
Mary-Margaret Chren, University of California - San Francisco

Abstract

Evidence-based dermatology has necessitated the development of rating scales that measure multidimensional and abstract constructs, such as quality of life. This article discusses some basic psychometric concepts, such as reliability, validity, standardization, and measurement precision, which need to be considered when choosing a clinical rating instrument. Also discussed is the impact of these parameters on increasing the statistical power of a clinical trial.